- Once you get to the diag page click on sever settings link
- Scroll down towards the section for: " TLS protocol versions supported for SMTP"
- Enable or disable necessary versions for Inbound or Outbound path from this page and click "Apply " at the bottom of the page
NOTE: Please be careful while making these changes as it will affect your mailflow if its dependent on TLS , DO NOT make any changes on this page unless you are sure of what needs to be done. These settings are available on version 8.1.x and later versions only